There are specific experts on this board on this topic but I would say YES.

Firstly lots of dogs swim when given the chance, fish wash up onshore etc, so it could easily have made up part of their diet thousands of years ago

Canned fish is less risky than fresh fish due to possible bacteria living in the various places where the fish may have been caught. I'd say canned tuna, salmon or mackeral is a good food source for dogs.

Fish can be PART of the dog's diet, but should not be the only element of its diet.

thanks for your reply, you have made my lovely dog very happy but she only eats fish say once a fortnight or month so i assume that is not too bad. she loves a nice fresh fillet from the market (a little spoilt, my husband does not get such good treatment) so she will be happy to hear the news, lets hope she doesnt get into salmon or i will go broke. thanks again

I agree with Homer - fish is a fine thing to add to the diet. My dogs getted canned mackerel (and salmon too when it's on sale) once or twice a week. High in Omega 3 and a high quality, low fat protein. Cooked fish is also fine, just remove all cooked bones.

Tuna might not be the best thing on a very regular basis, something to do with heavy metals in canned tuna.